Predictability of horizontal water vapor transport relative to precipitation: Enhancing situational awareness for forecasting western US extreme precipitation and flooding

TitlePredictability of horizontal water vapor transport relative to precipitation: Enhancing situational awareness for forecasting western US extreme precipitation and flooding
Publication TypeJournal Article
Year of Publication2016
AuthorsLavers D.A, Waliser D.E, Ralph FM, Dettinger MD
JournalGeophysical Research Letters
Volume43
Pagination2275-2282
Date Published2016/03
Type of ArticleArticle
ISBN Number0094-8276
Accession NumberWOS:000373109800060
Keywordsatmospheric rivers; california; hydrological extremes; impacts; madden-julian oscillation; moisture; predictability; system
Abstract

The western United States is vulnerable to socioeconomic disruption due to extreme winter precipitation and floods. Traditionally, forecasts of precipitation and river discharge provide the basis for preparations. Herein we show that earlier event awareness may be possible through use of horizontal water vapor transport (integrated vapor transport (IVT)) forecasts. Applying the potential predictability concept to the National Centers for Environmental Prediction global ensemble reforecasts, across 31 winters, IVT is found to be more predictable than precipitation. IVT ensemble forecasts with the smallest spreads (least forecast uncertainty) are associated with initiation states with anomalously high geopotential heights south of Alaska, a setup conducive for anticyclonic conditions and weak IVT into the western United States. IVT ensemble forecasts with the greatest spreads (most forecast uncertainty) have initiation states with anomalously low geopotential heights south of Alaska and correspond to atmospheric rivers. The greater IVT predictability could provide warnings of impending storminess with additional lead times for hydrometeorological applications.

DOI10.1002/2016gl067765
Student Publication: 
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